Brain-Whacking Games

What games especially puzzle/puzzler games have you played that you considered to be basically brain-whackers/brain-whacking games?

In my case I haven’t play any of these puzzle/puzzler games but after viewing/watching a number of gameplay footages as well as walkthroughs, I can say without AND beyond a shadow of a doubt that I definitely considered them to be real, true BRAIN-WHACKERS/BRAIN-WHACKING games:
Pneuma: Breath of Life
The Talos Principle
The Witness
MIND: Path to Thalamus

I’m more of a fan of the Professor Layton kind of Puzzle games, since they tend to have more charm then the 3D more abstract kind of puzzlers.

Also, absolutely loved Braid :grin:

I did finish Pneuma and it was a nice distraction with a nice coat of paint :sunglasses:

The Stanly Parable was kinda neat…I don’t know exactly if it fits, but trying to find all the various story paths can be a bit of a challenge.

Also…because I have to just throw this out there…Tetris.